What's the point of these 3 gas computers?

[DevonDiver]

There's no REQUIREMENT for anything. There are no governmental rules and regulations that say you must have this or must have that. Industry practice recommends a certain configuration for doing certain things, ...

Well, some things are required...or else you will die. Gas and a regulator are obvious examples.

When I say requirement, I mean... that the training, drills and procedures used in scuba diving are coherent with a requirement for a certain level of equipment.

Too little is insufficient and that is unsafe.

Too many is surplus...and that also degrades safety.

it's ridiculuous to do a cave dive, deep dive and think that ONE SPG setup is good enough without having another SPG setup for redundancy.

I suggest you do a little research.....

Google and forum search the word 'Hogarthian'.

I almost thought you were a troll until I then read this.........

I would not use a rec AI computer to do tech diving (not that I know anything about tech diving)..

So, maybe best stop using words like ridiculous when talking about tech/cave diving then?

You SPG people always claim that computers fail. Well, SPGs fail too, so why shouldn't you want to carry another SPG backup unit?

Ok...it basically works like this...

If you have a major equipment failure, then you abort the dive.

So, on a recreational dive...with no decompression...and within recreational dive limits.... and whilst maintaining the recommended minnimum reserve.... if your SPG fails... then you would immediately end the dive, ascend and leave the water.

You would not require a surplus SPG for the process of ascending from an aborted dive, because you would always have maintained a sufficuent reserve for exactly that situation.

To carry an extra SPG purely for the process of monitoring your air on ascent from an aborted dive would achieve no practical benefit.... but would provide the disadvantage of adding another failure point (something else likely to go wrong) to your overall configuration.

In addition, it provides another dangly, sticky-out protrusion just asking to get caught in line./net/kelp etc etc

In addition to that, it further adds to your task loading during the dive... placing greater stress on the diver...and that could provide an overload during an incident/accident/emergency.

So...for no discernable benefit, you are adding several obvious disadvantages to your equipment configuration.

So...again....SPG redundancy is not required.

 

[fnfalman]

You would not require a surplus SPG for the process of ascending from an aborted dive, because you would always have maintained a sufficuent reserve for exactly that situation.

To carry an extra SPG purely for the process of monitoring your air on ascent from an aborted dive would achieve no practical benefit.... but would provide the disadvantage of adding another failure point (something else likely to go wrong) to your overall configuration.

In addition, it provides another dangly, sticky-out protrusion just asking to get caught in line./net/kelp etc etc

In addition to that, it further adds to your task loading during the dive... placing greater stress on the diver...and that could provide an overload during an incident/accident/emergency.

So...for no discernable benefit, you are adding several obvious disadvantages to your equipment configuration.

So...again....SPG redundancy is not required.

So, for the reason above, SPG redundancy is not required, but somehow when using dive computer and the dive computer goes kaput, you can't simply abort the dive ala SPG going kaput?

I ain't no fancy cave/tech diver, but methinks something ain't right in Denmark.

 

[DevonDiver]

For recreational diving... the loss of a dive computer represents a different criteria of information,

With no SPG, you can ascend to the surface at the correct rate safely.

With no dive computer or depth gauge, you would have a far greater task in maintaining a safe ascent rate and safety stop.

That said, there is also no requirement for redundancy of a dive computer for recreational diving. Any diver should have the basic skills to abort a dive and maintain a slow ascent to the surface.,,,and, as you know, the safety stop is only recommended,, so missing it (whilst not ideal) is not a critical safety issue.

As is taught on the OW and AOW courses (and elsewhere), the correct response to the malfunction/failure of a dive computer is to immediately abort the dive and ascend, with buddy, to the surface.

The same response is true to any incident of major equipment failure on a recreational dive. The ability to immediately abort and ascend to the surface is what keeps recreational diving safe...and simple.

Technical diving is a completely different matter, as that immediate access to the surface is not available. With regards to computers... they transition from being 'dive profile guides' to becoming life critical instruments controlling a precise mult-stop decompression schedule. Thus, they need multiple redundancy.

However, even in technical diving, the issue of redundant SPG is governed by the same logic that applies to recreational use of the spg. The value of having it (little value) is outweighed by the drawbacks and hazards that a surplus spg would present.

Oh, and tech diving isn't about being 'fancy'...it is about applying precision, logic and strict rationale to your approach to diving, in order to off-set the much higher risks involved.

You should try it someday, it's a satisfying, challenging and rewarding pursuit....

 

[SelkieDVM]

If you point the transmitter down, parallel to the tank, the signal would be radiating towards the tank and the divers back, not toward the front, where a divers arm and receiver would be.

FWIW the transmitter on my singles reg works better in the down position than when pointing up, in fact I believe the manual recommends it be used that way (Uwatec Smart Z).

 

[FishOutUvH2O]

FWIW the transmitter on my singles reg works better in the down position than when pointing up, in fact I believe the manual recommends it be used that way (Uwatec Smart Z).

What 1st stage are using that you are able to run the transmitter parallel with the tank?

We tried an Uwatec (Galileo Sol), Oceanic, and Suunto transmitters. But, we did it on a doubles rig with Scubapro Mk25 1st stages. The way the 1st stages sat meant that the transmitters could either be pointed mostly "down" or "up" (up, was a snag hazard and didn't happen). We didn't have any single's regs that had an HP port to be able to get the transmitter pointed down. With the doubles set-up there were problems keeping a signal with all 3. I'd love to be able to point my transmitter down. It would be that much more tucked-away. But, my Atomic 1st just doesn't have any HP ports that I can do that with. My transmitter has no choice but to be perpendicular to the tank and at about a 45 deg. angle from the side of my head.

 

[SelkieDVM]

It's an Oceanic FDX10. It's not parallel to the tank, but at about 45 degrees. Still nicely out of the way. I also tried it just for yucks and grins on my doubles rig (SP MK16) but it had to face up and to the inside. Seemed to work ok but it hit my head too much and I didn't like the profile it presented.

 

[RJP]

What 1st stage are using that you are able to run the transmitter parallel with the tank?

With aqualung legend regs in doubles configuration, the transmitter for my Vytec DS points straight down parallel with the tank and in line with the neck of the tank.